Modular six-axis vision-haptic sensor calibration test platform

Abstract

A modular six-axis visual-tactile sensor calibration and testing platform includes: a fixed frame and a helical adjustable pressure module mounted thereon, a support device, a six-axis force sensor located within the support device, a precision rotation positioning platform relative to the fixed frame, a high-precision two-dimensional XY positioning platform mounted thereon, and a connector. The connector has a probe at its end, with the probe tip directly applying force to the contact surface. This invention meets the requirements for visual-tactile sensor testing and experimentation. Depending on the different sensing tasks required for testing the visual-tactile sensor, it integrates detection functional structures adapted to different situations.

Description

Technical Field

[0001] This invention relates to a technology in the field of visual-tactile sensing measurement, specifically a modular six-axis visual-tactile sensor calibration and testing platform. Background Technology

[0002] With the development of aerospace technology, the complexity and danger of space missions such as space station maintenance and satellite repair are constantly increasing, requiring aerospace robots with high-precision three-dimensional tactile perception to cope with complex interactive tasks in the space environment. Existing visual-tactile sensor stress loading technology can only achieve sample pre-compression and provide pressure load in the Z direction, and the structure is more complex, difficult to assemble, and the fixed structure is not conducive to testing samples of different sizes and thicknesses. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, this invention proposes a modular six-axis visual-tactile sensor calibration and testing platform that meets the requirements for visual-tactile sensor testing and experimentation. Based on the different perceptual tasks required for testing the visual-tactile sensor, it integrates detection functional structures adapted to different situations.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to a modular six-axis visual-tactile sensor calibration and testing platform, comprising: a fixed frame and a helical adjustable pressure module disposed thereon, a support device, a precision rotation positioning platform disposed relative to the fixed frame, a high-precision two-dimensional XY positioning platform disposed thereon, a connector, and a six-axis force sensor located on the connector, wherein: a probe is provided at the end of the connector, and the top of the probe directly applies force to the contact surface.

[0006] Technical effect

[0007] This invention addresses the shortcomings of current visual-tactile sensor testing platforms, such as large size, integrated design, and weak dynamic response, by providing a modular six-axis visual-tactile sensor calibration and testing platform. The invention provides a three-in-one displacement control device integrating a diverse indenter probe and rotation positioning platform, a high-precision two-dimensional XY positioning platform, and a Z-axis displacement stage. Compared to existing technologies, this invention can not only apply static pressure to the sensor but also load dynamic loads as needed. Furthermore, the overall device is compact and modular, facilitating adjustments based on different sensor requirements and conditions. This description also illustrates the influence of the probe's three-dimensional geometry on force test results, the relationship between Z-axis displacement and pressure, morphology, and the sliding path. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of the present invention;

[0009] In the diagram: 1. Precision rotation positioning platform; 2. High-precision two-dimensional XY positioning platform; 3. Connector; 4. Support device; 5. Pressure module for adjusting screw pitch; 6. Fixed frame; 7. Probe; 8. Six-axis force sensor.

[0010] Figure 2 for Figure 1 Enlarged view of a portion;

[0011] Figure 3 This is a schematic diagram of the probe;

[0012] Figure 4 This is a schematic diagram of the connector;

[0013] Figure 5 This is a schematic diagram of a fixed frame;

[0014] Figure 6 This is a schematic diagram illustrating the influence of the probe's three-dimensional geometry on force test results.

[0015] In the figure: (a) planar probe, (b) spherical probe, (c) needle-shaped probe;

[0016] Figure 7 This is a schematic diagram showing the calibration results for z-axis heights of 0.2mm, 0.5mm, 1.0mm, and 2.0mm.

[0017] Figure 8 This is a schematic diagram of the dynamic sliding process;

[0018] In the figure: (a) positive sliding first stage buckling, (b) positive sliding third stage buckling, (c) negative sliding second stage buckling. Detailed Implementation

[0019] like Figure 1 and Figure 2 As shown, this embodiment relates to a modular six-axis visual-tactile sensor calibration and testing platform, including: a fixed frame 6 and a helical adjustment pressure module 5, a support device 4, a precision rotation positioning platform 1 set relative to the fixed frame 6, a high-precision two-dimensional XY positioning platform 2 set thereon, a connector 3, and a six-axis force sensor 8 located on the connector 3, wherein: the end of the connector 3 is provided with a probe 7, and the top of the probe 7 directly applies force to the contact surface.

[0020] The top of the fixed frame 6 has a rectangular opening for mounting and observing samples. The fixed frame 6 is preferably prepared by 3D printing.

[0021] The pressure module 5 with adjustable screw pitch has a groove for placing the sample.

[0022] like Figure 3As shown, the probe 7 has a pointed shape and is preferably made of 3D-printed resin material.

[0023] The tip shapes include 100-micrometer and 200-micrometer spiked probes, circular planar probes with diameters of 2 mm, 3 mm, and 4 mm, oblong probes, and tip-recessed probes with embedded small balls of diameters of 2 mm and 4 mm.

[0024] like Figure 4 As shown, the connector 3 has an L-shaped protrusion, and the probe 7 is disposed at the end of the protrusion.

[0025] The connector 3 is connected to the force sensor via a high-precision displacement module fabricated by 3D printing. Considering the strength of the resin part, additional reinforcing ribs are provided at the corners to prevent the connector from breaking or tilting.

[0026] like Figure 5 As shown, the fixed frame 6 has a rectangular stepped viewing window inside.

[0027] This embodiment relates to a testing method for the above-mentioned device, including:

[0028] 1) Installation stage: Place the fixed frame on a flat surface, place the sample at the rectangular opening of the fixed frame, and connect the support device to it with bolts. Place the screw-adjustable pressure module on one side of the fixed frame to prepare for pre-applying axial load, and place the probe and six-axis force sensor at the bottom of the sensing element on the other side. Place the high-precision two-dimensional XY positioning platform and the precision rotation positioning platform on the same side at a position lower than the plane.

[0029] 2) Testing Phase: First, the sample is clamped in the support device 4 installed on both sides, and a transparent acrylic sheet is placed above the sample for fixation to prevent damage to the sample and the microscope or camera used for observation when load is applied; then, the pressure module 5 with screw pitch adjustment is further adjusted to compress the sample to form wrinkles; next, the universality and high sensitivity of the sensor are verified by using planar probes, spherical probes and needle probes of different shapes and sizes. The connector 3 and the probe are adjusted by adjusting the precise rotation positioning platform 1 and the high-precision two-dimensional XY positioning platform 2 set on it to make the probe contact the sample. The six-axis force sensor 8 records the magnitude of the force, and the microscope or camera records the morphology at this time; finally, a hemispherical probe with a diameter of 4mm is used for color calibration, and the color value of each position of the hemisphere is recorded for subsequent three-dimensional reconstruction.

[0030] By introducing a ribbed connector between the high-precision displacement module and the force sensor, this side device can achieve manual and automatic positioning in one, accurately control the contact between the probe and the sample, and the six-axis force sensor is connected to the PC to collect force and torque data, thus completing a test.

[0031] Through practical application experiments, the modular six-axis visual-tactile sensor calibration test platform of this invention was run according to the testing phase procedure. Different sized indenters were used to simulate touching different objects, including planar probes, spherical probes, and needle-shaped probes. The influence of the probe's three-dimensional geometry on the force test results was investigated. The results are as follows... Figure 6 As shown; to investigate the precision level of the system, a 4mm diameter spherical probe was selected, and the Z-axis compression depth was controlled in 0.1mm steps using a high-precision displacement platform. Simultaneously, a six-axis force sensor was used to collect the corresponding normal load, and the results are shown in the figure. Figure 7 As shown in Table 1, the data were also presented. Similarly, to explore the sensor's response to shear force and slippage behavior, translational and retraction experiments were further conducted. A linear motion path of ±5mm was set on a three-axis traverse platform to simulate real slippage operations. Simultaneously, images of morphological changes were recorded and matched with externally applied load data. The results are shown in Table 1. Figure 8 As shown.

[0032] Table 1

[0033]

[0034] Compared to existing technologies, this invention precisely locates the magnitude and direction of the applied load through multiple displacement platforms and connects the probe to a six-axis force sensor, analyzing the force-displacement-morphological images in a corresponding manner. It can perform testing tasks with various sensing requirements, including pre-applying axial compression loads to samples and collecting data under complex conditions such as static indentation and dynamic sliding. Compared to existing testing methods, it has advantages such as miniaturization, multifunctionality, modularity, and precision.

[0035] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A modular six-axis visual-tactile sensor calibration and testing platform, characterized in that, include: The fixed frame and the screw-adjustable pressure module, support device, precision rotation positioning platform set relative to the fixed frame, high-precision two-dimensional XY positioning platform set on it, connector, and six-axis force sensor located on the connector, wherein: the end of the connector is provided with a probe, and the top of the probe directly applies force to the contact surface; The top of the fixed frame has a rectangular opening for mounting and observing samples; The pressure module with adjustable screw pitch has a groove for placing the sample.

2. The modular six-axis visual-tactile sensor calibration and testing platform according to claim 1, characterized in that, The probe has a pointed shape, which includes 100-micrometer and 200-micrometer spiked probes, circular planar probes with diameters of 2 mm, 3 mm and 4 mm, oblong probes and tip-recessed probes that embed small balls with diameters of 2 mm and 4 mm.

3. The modular six-axis visual-tactile sensor calibration and testing platform according to claim 1, characterized in that, The connector has an L-shaped protrusion, and a probe is located at the end of the protrusion.

4. The modular six-axis visual-tactile sensor calibration and testing platform according to claim 1 or 3, characterized in that, The connector is reinforced at the corner to prevent it from breaking or tilting.

5. The modular six-axis visual-tactile sensor calibration and testing platform according to claim 1, characterized in that, The fixed frame is equipped with a rectangular stepped viewing window inside.

6. A testing method based on the platform described in any one of claims 1-5, characterized in that, include: 1) Installation stage: Place the fixed frame on a plane, place the sample at the rectangular opening of the fixed frame, and connect the support device on it with bolts. Place the screw-adjustable pressure module on one side of the fixed frame to prepare for pre-applying axial pressure load. Place the probe and six-axis mechanical sensor at the bottom of the sensing element on the other side, and place the high-precision two-dimensional XY positioning platform and the precision rotation positioning platform on the same side at a position lower than the plane. 2) Testing Phase: First, the sample is clamped in the support devices installed on both sides, and a transparent acrylic sheet is placed above the sample for fixation to prevent damage to the sample and the microscope or camera used for observation when load is applied. Then, the pressure module with adjustable screw pitch is adjusted to compress the sample to form wrinkles. Next, the universality and high sensitivity of the sensor are verified using planar probes, spherical probes and needle probes of different shapes and sizes. The connectors and probes are adjusted by adjusting the precise rotation positioning platform and the high-precision two-dimensional XY positioning platform set on it to make the probe contact the sample. The six-axis force sensor records the magnitude of the force, and the microscope or camera records the shape at this time. Finally, the color is calibrated using a hemispherical probe, and the color value of each position of the hemisphere is recorded for subsequent three-dimensional reconstruction.

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